JP3604351B2 - Resin bond wire saw - Google Patents

Description

注） 砥粒脱落個数は、顕微鏡観察により測定したワイヤソー１ｍｍ長さにおける砥粒脱落個数である。
【００２５】
表１からわかるように、発明品１，２は従来品に比して砥粒の脱落が少なく、総切り出し枚数は従来品の２〜４倍であった。メッキ層厚さの影響は、メッキ層厚さが厚いほど砥粒の埋設量が大きくなって砥粒保持力が高くなるので、砥粒の脱落が少なくなることが確認された。
【００２６】
【発明の効果】
レジンボンドワイヤソーの芯線の軟質金属メッキ層に砥粒の一部を強制的に埋設させることにより、砥粒はその一部が芯線表面の軟質金属層に食い込んだかたちとなって切断加工時の樹脂層の磨耗や振動などによっても砥粒が脱落しないようになり、ワイヤソーの長寿命化が図れる。
【図面の簡単な説明】
【図１】本発明の実施形態におけるワイヤソーの部分正面図である。
【図２】図１のＡ−Ａ線矢視による縦断面図である。
【図３】ワイヤソーの製造方法の説明図である。
【符号の説明】
１ 芯線
１ａ ピアノ線
１ｂ メッキ層
２ 砥粒層
２ａ ボンド層
２ｂ 砥粒
１０ 被覆ワイヤ
１１ 樹脂硬化後のワイヤ
１２ ワイヤソー製品
２０ 貯留槽
２１ 混合物
２２ ダイス
２３ 紫外線照射装置
２４ 加圧ローラ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fixed-abrasive wire saw using a resin bond, and more particularly to a resin-bonded wire saw having an enhanced function of preventing abrasive grains from dropping during cutting.
[0002]
[Prior art]
In the field of manufacturing various semiconductor devices, performance has been improved by miniaturization of wiring patterns.However, miniaturization of wiring patterns alone cannot keep up with multi-functionality. ing. With the increase in the size of such chips, silicon wafers with large diameters have been used from the viewpoint of improving the yield, and the cutting method from the silicon ingot, which is the preceding process, has also been changed from the conventional inner peripheral blade cutting method. The transition to the wire saw cut method, which can easily accommodate large diameters, is being made.
[0003]
One of the wire saw cutting methods that has been mainly performed in the past is a loose abrasive method using a slurry. In this loose abrasive method, a piano wire or ultra-high strength alloy wire is run in strong contact with the silicon ingot, and the free wire such as WA or GC is applied to the portion where the piano wire or ultra-high strength alloy wire is in contact. Cutting is performed while pouring lubricating oil containing particles. However, it is said that there is a limit to the cutting efficiency due to the deterioration of the working environment and the contamination of the work due to the scattering of the lubricating oil, and the inability to control the depth of penetration of the abrasive grains into the work material to be uniform. I have.
[0004]
On the other hand, in recent years, a fixed abrasive method using a wire saw in which abrasive grains such as WA, GC, diamond, and CBN are fixed to the peripheral surface of a core wire has been proposed. As a wire saw used in the fixed abrasive method, an electrodeposited wire saw for fixing the abrasive grains by electrodeposition and a resin bond wire saw for fixing the abrasive grains using a resin (resin) as a binder are known. Even with these electrodeposited wire saws and resin bond wire saws, cutting by abrasive grains is possible by running while strongly contacting the workpiece similarly to the loose abrasive method.
[0005]
By the way, since the electrodeposited wire saw spends time in a plating process for electrodepositing abrasive grains, it is practically impossible to electrodeposit abrasive grains on a core wire of several tens to several hundred km. In addition, there has been pointed out a problem in use that the breaking torsional strength and the bending strength are low, so that the wires are easily broken during processing. Thus, there is a history that a resin bond wire saw has been developed as an improvement over such a drawback of the electrodeposited wire saw.
[0006]
As such a resin bond wire saw, for example, there is a resin bond wire saw described in JP-A-10-138114. The resin bond wire saw described in this publication has a structure in which a high tensile strength metal wire is used as a core wire, and a polyamideimide resin is used as a binder and abrasive grains are dispersed and contained in the core wire to cover the core wire. According to such a resin-bonded wire saw, a long-distance wire saw, which has been difficult with an electrodeposited wire saw, can be manufactured.
[0007]
[Problems to be solved by the invention]
By the way, when cutting a silicon ingot or the like using a wire saw, there is a problem that abrasive grains easily fall off due to abrasion or vibration of a resin layer due to contact with a workpiece. To cope with this problem, Japanese Patent Application Laid-Open No. 10-328932 proposes a wire saw in which a fine dent is formed in the surface of a core wire and abrasive grains are inserted into the dent and fixed to the core wire.
[0008]
The wire saw described in the above publication forms an infinite number of satin-like dents on the core wire surface by a mechanical treatment such as sand blasting or shot peening or an electrochemical treatment such as chemical polishing or electrolytic polishing, and is a mixture of abrasive grains and a binder. Is applied to the surface of a core wire, squeezed with a dice to make the abrasive grains go into the recesses, to make the outer diameter uniform, and to fix the abrasive grains and the binder to the core wire by baking. It is said that such a wire saw can sufficiently withstand the reaction force even if the reaction force of the workpiece at the time of cutting acts on the abrasive grains.
[0009]
However, in the wire saw described in the above publication, although an increase in the adhesive force between the core wire and the resin layer due to an increase in the surface area of the core wire due to the formation of the dent can be expected, the abrasive grains only enter the dent. The effect of preventing the grains from falling off cannot be expected much. In addition, the formation of the dent by mechanical processing may damage the core wire and break the wire saw during cutting. In the electrochemical treatment, the core wire is hardly damaged, but it is difficult to form a dent enough to prevent the abrasive grains from falling off.
[0010]
On the other hand, apart from the method described in the above-mentioned publication, a special layer for bonding corresponding to an underlayer of a grindstone is formed on the surface of the core wire, or between the core wire and the resin layer using a surface modifier such as a coupling treatment. A method of sandwiching an adhesive layer between the layers may be considered. However, even in this method, the effect varies depending on the compatibility between the core wire material and the resin material, and the effect itself is slight.
[0011]
A problem to be solved by the present invention is to increase the adhesive strength of abrasive grains to a core wire in a resin bond wire saw to prevent the abrasive grains from falling off during cutting.
[0012]
[Means for Solving the Problems]
The present invention is characterized in that, in a resin bond wire saw in which abrasive grains are fixed to a surface of a core wire using a resin as a binder, a part of the abrasive grains is embedded in a soft metal plating layer applied to the core wire.
[0013]
As the core wire of the wire saw, a high-strength metal wire such as a piano wire or a high-strength metal wire whose surface is plated with a soft metal such as copper or a copper alloy is used. A high tensile strength metal wire plated with a soft metal such as an alloy is used, and a part of the abrasive grains is forcibly embedded in the plated soft metal layer. As a result, a part of the abrasive grains penetrate into the soft metal plating layer on the core wire surface, so that the abrasive grains do not fall off due to abrasion or vibration of the resin layer at the time of cutting.
[0014]
It is desirable that the thickness of the soft metal plating layer is 5 to 10 μm. If the thickness of the soft metal plating layer is smaller than 5 μm, the burying depth of the abrasive grains is too small and the effect of preventing falling off cannot be expected. When the diameter is larger than 10 μm, when the outer diameter is the same as that of the conventional product, the high tensile strength metal wire of the core material becomes too thin with respect to the diameter of the metal-plated core wire, which results in lower strength than the core wire. Is preferred. As the plating metal, gold, tin, zinc, an alloy thereof, or the like can be used in addition to copper or a copper alloy. By embedding a part of the abrasive grains only in the soft metal plating layer, the high strength metal wire as the core wire body is not damaged at all, and there is no danger of breaking the wire saw.
[0015]
The resin bond wire saw of the present invention is configured such that a core wire obtained by applying a soft metal plating to a high tensile strength metal wire is fed at a constant speed, and is passed through a coating tank storing a mixture of a liquid resin and abrasive grains to form a liquid resin and a abrasive on the core wire. A step of coating the mixture of grains, a step of curing the coated liquid resin to fix the abrasive layer to the core wire, and pressing the hardened abrasive layer by a pressure roller to form a part of the abrasive grains into the core wire. Embedded in the soft metal plating layer.
[0016]
Here, it is desirable to use a photocurable resin as the liquid resin. By using a photo-curing resin, it is possible to shorten the curing time of the liquid resin and increase the production efficiency, and by controlling the curing reaction in the resin curing process to temporarily create a low-temporary cured state. In addition, it is possible to bury the abrasive grains efficiently. Further, it is desirable to use a roller made of a material having a lower hardness than the high tensile strength metal wire as the pressure roller. When the abrasive layer is pressed by the pressure roller, when a part of the abrasive grains penetrates the soft metal plating layer and comes into contact with the high tensile metal wire of the core wire main body, it is lower than the high tensile metal wire as the pressure roller By using a material having a hardness, the abrasive grains do not bite into the high-strength metal wire even when further pressure is applied, and the high-strength metal wire is not damaged.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a partial front view of a wire saw according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view taken along line AA of FIG.
[0018]
The wire saw of the present embodiment is obtained by fixing an abrasive layer 2 to a core wire 1, and the core wire 1 is obtained by plating a piano wire 1 a having a wire diameter of 0.15 mm with a Cu—Zn alloy. It is a soft metal layer having a thickness of 7 μm. The abrasive layer 2 has the abrasive particles 2b fixed by the bond layer 2a. The bond layer 2a is a resin bond in which a filler material is mixed with an acrylate resin to which a photo radical generator has been added, and the abrasive grains 2b are diamond abrasive grains having an average particle diameter of 25 μm.
[0019]
Here, in the wire saw of the present embodiment, a part of the abrasive grains 2 b is embedded in the plating layer 1 b of the core wire 1. Partial embedding of the abrasive grains 2b in the plating layer 1b is performed by pressing the abrasive grain layer 2 after the hardened bond layer 2a covering the core wire 1 with the abrasive grains 2b by a pressure roller. At this time, by using a roller of a material having a hardness lower than that of the piano wire 1a as the pressure roller, as shown in FIG. 2, the abrasive grains 2b do not penetrate into the piano wire 1a, and the abrasive is reliably applied to the plating layer 1b. Part of the grains 2b can be embedded. As a result, a part of the abrasive grains 2b bites into the plating layer 1b, so that the abrasive grains 2b do not fall off due to abrasion or vibration of the bond layer 2a at the time of cutting using a wire saw.
[0020]
FIG. 3 is an explanatory diagram of a method for manufacturing a wire saw according to the present invention. The main steps of the manufacturing method are as follows. The core wire 1 unwound from a reel (not shown) is sent out at a constant speed, and the core wire 1 is passed through a storage tank 20 for storing a mixture 21 of the abrasive grains and the liquid resin. Is coated. The coating thickness of the coating wire 10 that has passed through the storage tank 20 is made uniform by the die 22, and then the liquid resin of the coating layer is cured by the ultraviolet irradiation device 23. The wire 11 after the resin is cured is pressurized on the entire circumference of the wire by a pressure roller 24, and a part of the abrasive grains 2b is embedded in the plating layer 1b of the core wire 1 as shown in FIG. obtain.
[0021]
In the storage tank 20, a mixture 21 in which diamond abrasive grains having an average particle size of 25 μm and a filler material are mixed with an acrylate resin is stored. The die 22 is for adjusting the outer diameter by removing a mixture excessively attached to the coated wire 10. In the case of the present embodiment, the finished outer diameter after passing through the die 22 is 0.21 mm ± 10 μm. is there. The ultraviolet irradiation device 23 sends the wire 10 to the ultraviolet irradiation device 23 by setting the distance to the die 22 and the wire feed speed so that the wire 10 reaches within 5 seconds after passing through the dice 22, and irradiates the ultraviolet light. The resin in the coating layer is cured to form the abrasive layer 2.
[0022]
The pressure roller 24 is a roller in which two rotating rollers each having a semicircular groove having a size corresponding to the finished outer diameter of the wire saw formed on the peripheral surface thereof are opposed to each other. Is embedded in the plating layer 1a of the core wire 1. The pressure roller 24 is made of a resin having a lower hardness than the piano wire 1a of the core wire 1 of the wire saw, and there is no possibility that the abrasive grains 2b damage the piano wire 1a when the wire 11 is pressed by the pressure roller 24.
[0023]
(Test example)
In order to confirm the effects of the present invention, the invention 1 in which the plating layer thickness of the core wire 1 is 5 μm, the invention product 2 in which the plating layer thickness is 10 μm, and the pressing by the pressure roller in the wire saw of the above embodiment. A cutting test was performed under the following test conditions using each of the conventional wire saws that were not subjected to the following.
Cutting device: Single wire cutting device Wire speed: 400m / min on average
Wire tension: 19.5N
Workpiece: Silicon ingot [0024]
Table 1 shows the dropping state of the abrasive grains of the wire saw when the number of cutouts is 50 and the total number of cutouts that can be cut out with a predetermined processing accuracy.
[Table 1]

Note) The number of abrasive grains dropped is the number of abrasive grains dropped at a wire saw length of 1 mm as measured by microscopic observation.
[0025]
As can be seen from Table 1, the invention products 1 and 2 had less abrasive grains falling off than the conventional product, and the total number of cut out pieces was 2 to 4 times that of the conventional product. It was confirmed that the influence of the thickness of the plating layer was such that the larger the thickness of the plating layer, the larger the amount of buried abrasive grains and the higher the abrasive grain holding power.
[0026]
【The invention's effect】
By forcibly embedding a part of the abrasive grains in the soft metal plating layer of the core wire of the resin bond wire saw, the abrasive grains are partially cut into the soft metal layer on the core wire surface and the resin during cutting processing The abrasive grains do not fall off due to wear or vibration of the layer, and the life of the wire saw can be extended.
[Brief description of the drawings]
FIG. 1 is a partial front view of a wire saw according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view taken along line AA of FIG.
FIG. 3 is an explanatory diagram of a method for manufacturing a wire saw.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Core wire 1a Piano wire 1b Plating layer 2 Abrasive layer 2a Bond layer 2b Abrasive particles 10 Coated wire 11 Wire after resin hardening 12 Wire saw product 20 Reservoir 21 Mixture 22 Dice 23 Ultraviolet irradiation device 24 Pressure roller

Claims (3)

A step of coating the mixture of the liquid resin and the abrasive grains on the core wire by passing the core wire obtained by applying the soft metal plating to the high-strength metal wire at a constant speed, passing the coating tank storing the mixture of the liquid resin and the abrasive grains; Curing the coated liquid resin to fix the abrasive layer to the core wire, and pressing the hardened abrasive layer with a pressure roller of a material having a lower hardness than the high tensile strength metal wire to form the abrasive particles. Embedding a portion in a soft metal plating layer of a core wire. The method for manufacturing a resin bond wire saw according to claim 1, wherein a photocurable resin is used as the liquid resin. A step of coating the mixture of the liquid resin and the abrasive grains on the core wire by passing the core wire obtained by applying the soft metal plating to the high-strength metal wire at a constant speed, passing the coating tank storing the mixture of the liquid resin and the abrasive grains; Curing the coated liquid resin to fix the abrasive layer to the core wire, and pressing the hardened abrasive layer with a pressure roller of a material having a lower hardness than the high tensile strength metal wire to form the abrasive particles. And a step of embedding a part in a soft metal plating layer of a core wire.A resin bond wire saw manufactured by a method of manufacturing a resin bond wire saw including a step of embedding a part of abrasive grains in a soft metal plating layer applied to a core wire , A resin bond wire saw, wherein the thickness of the soft metal plating layer is 5 to 10 μm .

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